Section 1: Diet and supplements
It is sensible for pregnant women to be advised to eat a healthy, balanced diet, including fresh fruit and vegetables.
Average weight gain in pregnancy should be about 6kg. Obese women (BMI >30kg/m2) should try not to gain any extra weight but should be advised to eat a healthy diet without calorie restriction.
Constipation is a common problem in early pregnancy. Increasing fibre intake and drinking plenty of water is usually effective.
Women should be advised to monitor their intake of some foods; for example, liver contains excessive levels of vitamin A and should be eaten only in moderation.
Supplements and folic acid
Neural tube defects (NTDs) complicate about one in 650 pregnancies in the UK.
There is strong evidence to support supplementation with folic acid both before conception and during the first three months of pregnancy to reduce the risk of NTDs. The dosage usually recommended is 400 micrograms of folic acid per day.
While it is true that the demand for iron increases in pregnancy, routine supplementation has not been shown to improve outcomes.
A woman is considered to have anaemia in pregnancy if she has a blood haemoglobin concentration of <11.0g/dl at the time of booking in and <10.5g/dl at 28 weeks' gestation, which is common in pregnancy.
In women with haemoglobin levels below these thresholds, investigations should include measurement of ferritin and, possibly, red-cell folate and vitamin B12. Consideration should also be given to the possibility of haemoglobinopathies, especially in relevant ethnic groups.
In simple iron-deficiency anaemia, iron can be prescribed.
Proven vitamin deficiencies are rare in the UK and vitamin supplements are best avoided in early pregnancy. If they are required later in pregnancy for clear reasons, women should be encouraged to use formulations that are designed specifically for use in pregnancy.
There is evidence to suggest that too much vitamin A can be harmful, particularly in the first trimester. There is a recognised association between excessive vitamin A and fetal anomalies.
Obesity in pregnancy
Women with a BMI >30kg/m2 are at an increased risk during pregnancy of thromboembolism, hypertension and cardiac problems, with a much higher incidence of emergency caesarean section and shoulder dystocia.
Women with a BMI >30kg/m2 should have a consultant obstetric and anaesthetic review.
About 40 per cent of women who drink alcohol continue to do so during pregnancy. Fortunately, most drink only small amounts.
Fetal alcohol syndrome consists of fetal growth restriction, neurological abnormalities and characteristic facial deformities. It is seen in approximately 30 per cent of births in women who consume more than 18 units of alcohol per day throughout their pregnancy.
Alcohol consumption of more than 15 units per week is associated with a reduction in the birthweight.
The recommendation from the Royal College of Obstetricians and Gynaecologists is that alcohol consumption should be limited to fewer than seven units per week, with no more than one unit of alcohol per day, and avoided in the first three months of pregnancy.
Section 2: Infections and vaccinations
Contact with chickenpox
Most adults in the UK are immune to the chickenpox virus (Varicella zoster) and consequently, chickenpox in pregnancy is a rare event that complicates only three in 1,000 pregnancies.
When it occurs in a pregnant woman who is not immune, however, it can have serious consequences for mother and baby. In pregnancy, chickenpox is associated with pneumonia, hepatitis and encephalitis.
Before 20 weeks' gestation, infection of the fetus is associated with fetal varicella syndrome. This is characterised by eye defects and neurological abnormalities.
Between 20 and 36 weeks of pregnancy, maternal infection does not appear to be associated with any effects on the fetus. After 36 weeks, up to 50 per cent of babies are infected.
Severe chickenpox infection in the baby is likely if it is born within seven days of the maternal rash. If a mother is in contact with chickenpox during the infectious window and there is any doubt about her immunity, her serum should be tested for antibodies.
Women who develop chickenpox should be offered oral aciclovir if they are more than 20 weeks pregnant.
Live vaccines are contraindicated in pregnancy.
Contracting yellow fever is fatal in 50 per cent of cases, so travel to endemic countries should be avoided. If the patient must travel, vaccination may be considered after 24 weeks of pregnancy, when the risk/benefit ratio tips in favour of doing so.
In general, killed or inactivated vaccines and toxoids are safe in pregnancy. Oral polio vaccine is also safe.
If a pregnant woman is travelling to a malaria-endemic region, she should be advised to take the usual precautions to minimise exposure. Chloroquine and proguanil can be prescribed for travel to areas where malaria strains are not resistant. Malaria is extremely serious, with a maternal mortality rate as high as 10 per cent.
Toxoplasmosis is caused by the parasite Toxoplasma gondii. If the mother is infected during pregnancy, it may be transmitted to the fetus and can cause severe problems at birth.
The most common way to acquire the parasite is by eating undercooked meat, or by contact with cat faeces.
Pregnant women should be advised to ensure that meat is properly cooked and that gloves are worn when working in the garden or cleaning cat-litter trays.
Listeriosis is caused by Listeria monocytogenes and infection during pregnancy is asso-ciated with miscarriage, stillbirth and infection in the baby.
Listeriosis is acquired from unpasteurised milk, ripened soft cheeses made from unpasteurised milk, and pate, all of which should be avoided in pregnancy. L monocytogenes can multiply at low temperatures, so can therefore occur in some refrigerators.
Pregnant women should also be advised to avoid some uncooked foods, such as raw cabbage, cooked foods that are inadequately reheated and undercooked foods.
The diagnosis is made by the clinical picture, blood cultures and serology. If suspected, listeriosis can be treated with amoxicillin or erythromycin. Severe identified cases may need IV antibiotics.
Section 3: Frequently asked questions
There is no evidence to suggest that sexual activity is harmful during pregnancy, provided there is no discomfort.
Changes in technique and position may be necessary to avoid this, but even in late pregnancy there should be no worrying consequences.
Exercise during pregnancy
There is no evidence that moderate exercise in pregnancy is detrimental to the outcome. For most women, it is beneficial to continue with appropriate exercise. Horseriding is not recommended, and pregnant women should be advised to avoid scuba diving because the physiological effects of changes in oxygen tension, nitrogen solubility and hydrostatic pressure at depth are not clearly understood.
Air travel in pregnancy
There is no evidence that air travel is detrimental to pregnancy. Long-haul travel is known to be associated with an increased risk of DVT, but whether this risk is greater in pregnancy is not known.
General advice to avoid alcohol and to keep well hydrated during the flight is important, and women should be encouraged to move around as much as possible. Correctly fitted compression stockings may also reduce the risk.
Pregnancy after 40 weeks
Most women (82 per cent) will deliver by 42 weeks. Pregnancies extending beyond this are associated with increased perinatal morbidity and mortality.
A membrane sweep at 41 weeks has been shown to reduce the need for formal induction of labour and is not associated with any adverse neonatal outcomes. If a woman chooses not to be induced, intensive fetal surveillance should be undertaken from 42 weeks.
Elective caesarean section
Caesarean rates continue to rise. Although an elective caesarean section is safe, when compared with vaginal birth, the rate of complications is higher and they are often more serious.
There is also increasing evidence that a caesarean section in the first pregnancy has a negative effect on outcomes of future pregnancies, with increased rates of stillbirth, infertility and placental problems.
It should be made clear to women thinking of choosing a caesarean section that it is not the easy option.
Section 4: Diabetes and other high risks
Women with existing medical conditions, or who develop a problem during pregnancy, will need referral for consultant obstetric care.
Ideally, women with medical conditions that may be adversely affected by pregnancy, or may alter the outcome of a pregnancy, should have an appointment before they conceive.
This allows them to make informed choices about pregnancy, the risks and possible outcomes. An appointment before the woman becomes pregnant allows for a review of any medication she may be taking and offers the opportunity to change it if needed. A detailed plan for the pregnancy can then be developed.
Type-1 diabetes is the most common existing medical condition seen in pregnancy and outcomes remain poor. Congenital abnormality rates are as much as three times the background rate and there is also a greatly increased perinatal mortality rate.
Women with diabetes who are planning a pregnancy should be given dietary advice and encouraged to take folic acid supplements, and should plan in advance to optimise their blood glucose control. These measures have been shown to improve pregnancy outcomes, but they are not well adhered to by women with type-1 diabetes.
The NSF for diabetes has recommended that all obstetric units provide a multidisciplinary clinic to give pre-pregnancy advice for this high-risk group.
The Confidential Enquiry into Maternal and Child Health has reported that only 17 per cent of obstetric units provide such a service. Until this situation improves, any healthcare professional looking after women with diabetes must offer advice about pre-pregnancy planning at every opportunity.
As type-2 diabetes rises in the younger population, the number of pregnant women with diabetes is also increasing. It is becoming clear that the outcomes from pregnancies complicated by type-2 diabetes are as poor as those from type-1 diabetes.
Good pre-pregnancy care is vital and women with type-2 diabetes should be encouraged to improve their blood glucose control before becoming pregnant. Traditionally, women stop taking oral hypoglycaemic drugs and change to insulin either before, or early in, pregnancy. Some insulin-resistant women with type-2 diabetes have taken metformin in pregnancy, however, and the results have been very promising.
Other medical conditions, such as epilepsy, cystic fibrosis and heart disease, remain relatively rare in pregnancy.
When they do occur, they demand specialist input and care in a dedicated obstetric medicine clinic.
This article was originally published in MIMS Women's Health. To subscribe go to www.hayreg.co.uk/specials
Women with pre-existing medical conditions or who develop a problem during pregnancy will need referral for consultant obstetric care.
- A pre-pregnancy appointment allows for a review of the risks, outcomes and medication.
- Congenital abnormality rates are high in diabetic mothers and there is an greatly increased perinatal mortality rate.
- Pre-pregnancy planning improves outcomes in diabetes, but provision of specialist clinics is inadequate.